Octadecanoic Acid

CAS Number:

57-11-4

Chemical / IUPAC Name:

Octadecanoic Acid

INCI Name:

 Stearic Acid

Molecular Formula:

C18H36O2

Molecular Weight:

 284.48 g/mol

EC Number:

200-313-4

Other Names:

Cetylacetic Acid, n-Octadecanoic Acid

Uses:

Stearic Acid is a saturated long-chain fatty acid that is one of the most common and versatile ingredients in cosmetic and industrial formulations. It appears as white, waxy flakes or pellets .

· Cosmetics & Personal Care: Widely used as an emulsifier, thickener, and stabilizer in creams, lotions, foundations, and shaving creams. It helps create stable emulsions and provides a rich, luxurious texture .

· Soap Making: A key component in soap bars, where it reacts with alkalis to form soap and provides hardness, stability, and a creamy lather .

· Hair Care: Used in conditioners and styling products to add body and control .

· Industrial Applications: Functions as a lubricant, mold release agent, and in the production of rubber, plastics, and candles .

Origin

Stearic Acid is a naturally-derived fatty acid obtained from vegetable and animal sources. It is produced by the hydrolysis (splitting) of triglycerides from sources like palm oil, coconut oil, or tallow, followed by hydrogenation and fractionation. Vegetable-derived stearic acid (often from palm) is most common in cosmetics .

What does Stearic Acid do in a formulation?

• Emulsifying Agent: Helps stabilize oil-in-water emulsions .
• Viscosity Modifier / Thickener: Increases the thickness and body of formulations .
• Opacifying Agent: Contributes to the opaque, creamy appearance of products .
• Emollient: Provides a soft, smooth feel to the skin .
• Surfactant: Functions as a cleansing and foaming agent in soaps .
• Binder: Helps hold pressed powders together .

Safety Profile:

· General Hazard Classification: Considered safe for use in cosmetics at typical concentrations. It is generally recognized as safe (GRAS) by the FDA for food use .

· Irritation & Sensitization: Generally regarded as non-irritating and non-sensitizing to skin and eyes at typical use concentrations .

· Purity: Cosmetic and food-grade stearic acid is highly purified .

· Vegetable vs. Animal Source: Vegetable-derived stearic acid is preferred for vegan and plant-based formulations .

· Regulatory Status: Approved for use in cosmetics worldwide. Meets pharmacopoeia standards (USP, NF, Ph.Eur.)

Technical profile: